Saturday, 16 July 2016

Kangos upstairs

The previous post dealt with how the decision to have the internal cement plaster taken off the stone walls upstairs arose.  Although it didn't at the time influence the decision-making (perhaps it should have),  it is worth also mentioning an issue which I had begun to notice in 2015 as it had gradually built up (I'm not the most observant of people).  Wooden doors, bannisters and mantelpieces upstairs (painted in non-breathable acrylic paint) were accumulating a black mould.








This was not happening to doors downstairs (where almost all cement had been removed).  For a time I was mystified about this and later inclined to think it solely due to insufficient vapour extraction from the upstairs bathrooms.  I now think the lack of internal breathability of any of the upstairs walls must have been at least partly the issue.  Although it wasn't a driver of the decision to remove the concrete when that decision was taken, I hope and expect this issue will not recur in future now the upstairs walls are breathing.

Fast forward to March.... out goes all the bedroom furniture to be stacked in a covered pile in the sitting room and in comes protective hardboards for the flooring (fingers crossed - they're still in place at time of writing) and the kango hammers.  The ensuing mess and cloud of dust was in some respects the hardest of the several phases I've experienced with this rolling project.  There was no sanctuary this time.   Visiting involved airbnbing in the locality.



At one stage it was literally crawling between rubble and scaffold bars to get upstairs

One of the 2 previously covered fireplaces plus the original back window from before the addition of the mid C19th annex



The mid C19th annex upstairs with the other rediscovered fireplace





While the destruction phase was going on my main job was to decide on the lime plaster to go onto the walls.  Needless to say, I (over)analysed the options and probably tried the patience of Kevin and Pat in the process.  The suggestion had been to use Secil Ecocork which is a significantly breathable lime plaster system from Portugal which has some insulating properties in addition to its breathability.  This product seems to have achieved a broad degree of acceptance within the community working with lime in Ireland in recent years.  It is frequently used on stone walls with what seems a good track record to date.

A couple of months earlier, at the same time as the work on the attic, it was used in two small areas downstairs which I asked Pat and Kevin to work on as an 'experimental canvass' - a porch area out of which I was moving a boiler and the dank and windowless small toilet in the north east corner of the house.  I had been satisfied with the results to date.



External walls of porch plastered with Secil Ecocork plaster system


On the other hand, the plastering job to come upstairs would probably be the largest order for internal plaster I would make ever and I wanted to try and make sure it was fully thought through. Do it once and try not to have regrets later!

I struggled a little because there is a whole world of internal lime plasters and it can be confusing for the uninitiated to find their bearings.  I researched online, sent a question out to a LinkedIn building conservation group, asked Pete Ward and gradually concluded there were 2 broad options:
1) hydraulic lime mortars (plasters which set faster and harder giving more strength but as a tradeoff are somewhat less porous depending on the natural hydraulic lime 'NHL' strength of the makeup) 
2) non hydraulic, 'fat' or 'soft' lime plasters (which have a much slower set and give you a softer-looking plaster with maximum breathability)

The hydraulic lime mortars, because of their strength, are used for almost all outdoor lime rendering and had been used by Kevin and Pat in 2014 on the external lime rendering of my house (an NHL 3.5 mix in that case).   They are also often used for internal plastering and the Secil Ecocork is is a pre-mixed hydraulic lime plaster system - this is arguably part of its success in terms of uniformity of resulting performance and lower risk in application.

For me, if I was going to undergo all the destruction of removing cement, then I wanted to replacement lime plaster to have maximum breathability - why settle for less?  The reason why you might settle for a little less breathability is that hydraulic lime plasters with added aggregate (for example cork) can have slightly higher insulating characteristics than a soft lime plaster.  As far as I could glean, strength of plaster and/or insulating properties come at the expense of ultra-breathability.

Given this trade-off, Pete Ward's observation that the thermal mass of 2ft-plus thick solid walls constitutes  your real insulation was the cardinal point to bear in mind.  One of the other contributors on the linkedin conservation group put it nicely: 'the (thermal) specification of a few mm of inner wall covering is not going to make much difference one way or another. Re vapour permeability - go for the most porous, as the walls should be able to act as moisture reservoirs - dependent on environmental conditions'

Once I had that direction, the decision became easier; I considered asking Kevin and Pat to add lime putty to the Secil Ecocork system to take it down from NHL3.5 (I believe, although its hard to tell from the product literature) down to something like a very breathable NHL2.  In the end though, given I wasn't under any time pressure and could take time for plaster to set, I opted for the ultra-traditional choice for internal plaster on these islands; soft lime hemp plaster.

Soft lime hemp takes patience in application and then in waiting before it can be painted. To give an idea, the application of coats started in the second week of April and Kevin and Pat were still being cautious about painting one section of plaster on a shaded east facing wall late in June.

Time and performance (i.e. breathability) will be the test of the success or otherwise of this plaster choice.  The initial result however, from an aesthetic viewpoint (I write this as the furniture begins to go back into the bedrooms) is very pleasing - a plaster with an soft-edged organic look and feel to it.
Undercoats




Final coat beginning to dry in May

Fat lime plaster can give pleasing organic shape to corners






Next post:  a nasty surprise uncovered ...

     





Saturday, 11 June 2016

Upstairs inside walls - to leave under cement or not?

Alongside the insulation of the attic which proceeded at pace during January, the knotty issue of what - if anything - to do with the cement-plastered inside of the external walls upstairs was decided during that month.  As usual, the decision required me to spell out what I was looking to achieve (bedrooms that could feel warm and retain heat even in winter cold snaps) followed by an examination of the options with Pete Ward and Kevin+Pat at Midwest Lime to see if any option represented an improvement worth the investment.  In the end, this process led me to question and alter what I was looking to achieve as I learned, understood and thought more.

By now, the interior of the house upstairs was (apart from the fitted kitchen area) the last remaining substantial zone of cement plastering.  The work in 2014 had first prioritised the external rendering and then removal of cement from downstairs interior  (creating a ground floor internal 'evaporation zone' for the rubble stone walls).  Through all the building works, upstairs had been the refuge - no dust, continuously furnished, functioning radiators etc.

However, I always had a nagging unease about leaving upstairs as it was - combined with no appetite to extend cement hacking and dust clouds into our bedrooms.   At the back of my mind the answer from the conservation architect during his one hour verbal on-site consultation in Sept 2013 still echoed:
Me: 'how much cement needs to come off eventually?'
Conservation architect: 'ultimately - ideally and if possible - all of it should come off..... even if not all of it may need to be removed to fix the current damp problem'

Also gnawing at the back of my mind was awareness that cement-plastered walls can feel cold and although recent winters since I acquired the house had been relatively mild, I knew that the previous owner had found some of the bedrooms - in particular the one above the kitchen in the C19th annex which had 3 external walls - chilly during the more epic winters like 2010/11.    

I spent January exploring what insulation might be possible to retro-fit onto the cement plaster on the internal side of the external bedroom and upstairs landing walls.  I vaguely imagined some sort of insulating panels that could be fixed on and lightly plastered over with relatively little destruction.

Because I was looking to retrofit insulation onto an non-breathing internal cement plaster, my research started off seeking to establish whether, logically, it made no odds if that insulation was breathable or not.  In other words, was there any need to go for more expensive breathable insulating boards like Gutex or Calsitherm.

So what did the initial research (through online reading and calling suppliers) teach me and the builders?:
1) Even if retrofitting insulation onto cement, it did matter that this insulation be breathable.  Otherwise warm internal air would condensate when it hit the cold cement and (because it wouldn't be able to pass through the cement or back out through the insulation)  moisture would be trapped between the insulating board and cement ... a worse state of affairs than the status quo
2) Not not only did it matter that the insulation be breathable, it needed to be highly breathable - the highest spec available, which meant Calsitherm or its equivalent.  Gutex would not be breathable enough in this particular circumstance up against cold cement.

And this was the point at which the scope of what was on the cards for upstairs changed radically.   Calsitherm and its equivalent highly breathable calcium silicate insulating boards are not cheap, currently at least.  The cost estimate for material and labour to retrofit this onto the cement plaster was approximately the same as the cost estimate for putting hardboards down upstairs, hacking off the infernal cement altogether and replastering with lime.

So - not quite appreciating what the reality of losing the bedrooms and extending the cement dust cloud upstairs would prove to be like - I opted for 'so long cement, miss you not'.  

Next post: Kangos upstairs...

As this has been a shamefully photo-less post, some gratuitous unrelated before-and-after which may not make it into another post. One of the side jobs I'd asked Pat and Kevin to do while onsite was scooping out the infilled inglenook in what had once been the kitchen prior to the adding of the c19th annex:

Again, huge credit to Pete for guiding us on this and explaining breadovens!

 This ....

Became this .....





Then later this .....





And is now this ......


 


 

Sunday, 31 January 2016

Back at it - the attic

2015 turned out to be a "year off" in terms of new phases of the restoration.  Early months of the year were spent cleaning and hoovering dust from knocking out an internal wall in Dec 2014 which provided light and ventilation to the kitchen.  This room is situated in a northwards-protruded mid /c19th annex to the original building and its original chimney flu has been closed since an oil-fired range cooker was installed 13 years ago depriving it of its original source of ventilation (contributing to the teabag episode mentioned in the first post).  Destruction and specification fatigue on my part was compounded by illness in the family and the year proceeded dominated by other life priorities.

Christmas 2015 I met again with Kevin from Mid West Lime to discuss sequencing of remaining work. Despite the fact that, internally, the upstairs had not been touched whereas downstairs resembled a cave (with mostly bare rubble walls hacked of their recent cement render and with radiators removed), my preference for the next stage was to prioritise upstairs.  I knew (since the original purchase survey) that the attic insulation was insufficient and would need addressing.  I also was clear in my own mind that all the restoration effort would be of limited use if the house didn't end up being able to feel warm in cold months.  Therefore, I wanted to work out what insulation could be retro-fitted to the inside of the external walls upstairs. I wanted to address both these aspects before moving onto sorting out downstairs.  I wanted one area of the house at least to be 'done'.  I also didn't fancy the idea of finishing downstairs only to have builders later marching through it to work on upstairs.

As usual, there were a number of insulation options to consider in order to decide on a spec.  Kevin and Pat were very helpful in teasing out for me what these options entailed and, as in the past, I also turned to Pete Ward to see what he thought.   Decisions become clearer after chatting through with Pete, even where you may already  have tentatively reached that decision.  Although the broad spec for the upstairs wall insulation was decided at this point, this work won't take place until spring.  The attic, on the other hand, proceeded quickly when a cold snap in January meant Kevin, Pat and team couldn't continue on an existing job outdoors for another client and we pressed 'go' at short notice.

The roof had been newly constructed to replace the previous one 13yrs earlier at the time the house was entombed in cement.  I learned from a builder who had been involved that internal walls running up into  the attic with doorways in them (remaining from a time when the house had had a third storey) had also been lowered down to 2nd storey ceiling level.   10cms of fibreglass insulation had been laid between the joists in line with insulation standards of the time.  At some point rodents had moved in as this fireglass was fouled with a lot of droppings.  Not pleasant and in need of removing!

More recent thought on insulation best practice is 30cms thickness so that much was a given.  The  decision-making revolved around what material to insulate with and what flooring might make sense, if any.  The pitch of the roof meant that the attic space itself was too low for living space and in any case was intersected by cross beams.  Nevertheless, I was keen to put some flooring down as part of the insulation work in order to gain some storage space.  Kevin educated / persuaded me that this was only worthwhile in the central part where the roof wasn't too low and that to the sides the insulation could just pile up.   9" timbers onto which the flooring would be nailed would be laid cross-ways on the existing joists leaving ~15" gap below to fit the insulation.  But what insulation?   

Choice boiled down to three materials: (more) fibreglass, cellulose or sheep's wool.  The former is pretty nasty stuff which disintegrates with time so was never a contender really.  Cellulose was seriously considered.  It's accessible in terms of price, has some eco credentials (its seems to be formed from recycled and treated paper / cardboard) and has been gaining in levels of adoption.  However, it seems fair to say it is too new to judge how it will fare against the test of time. Sheep's wool was the high quality / low risk option all along.  Its not cheap and I needed some time to justify the higher cost vs. cellulose to myself.  In the end, the unanimity of the endorsement of the quality of the product from practitioners (pure sheepswool that is, there are some adulterated products available also) in all aspects of performance - including proven integrity and persistence through time - swayed me.  It was the 'sleep easy' choice.  Nice also that it's made in Ireland!  Aisling at sheepwoolinsulation.ie was very helpful and I must say, now that it's laid, the wool has a lovely feel to it on any occasion in the attic when I brush against it.       





Nothing has been straighforward with this house and so, naturally, an unexpected issue arose once we'd been spending quality time getting to know the attic space.  I had seen that vents had been built into the space and assumed the roof was one area of the work from 13 years previously which had been well carried out.  However, Kevin correctly pointed out to me that one vent in the roof slate and one vent in the soffit does not really constitute adequate ventilation for an attic space that size.  To make things worse, the extractor fan from the bathroom is venting steam into the attic rather than outside the building!  So we have another issuette to fix. Currently we are trying to work out how best to do. Hopefully we will be able to decide on a plan to add onto the next phase of work in March. Onwards and upwards!



Wednesday, 31 December 2014

Pain with the windows

One of the likely problems where a traditional stone building has had a cement render imposed on it is that dampness that will inevitably get trapped in the wall may lead to window frames deteriorating.  Evidence of this had been visible even before the exploratory work had begun.








As Kevin and Pat helped me work through defining the scope of the re-render, one of the biggest questions to answer was how to treat the windows and how many of the windows needed work?  The windows are modern hardwood double-glazed spring-balanced sash; same age as the cement renovation - about 12 years old.  It was obvious that the frames of the 4 ground floor windows facing south into the elements needed repair (pics above are one of these windows from the inside).  Some probing with a car key was enough to confirm that the 5 windows on the upper floor similarly needed repair.

And the specification for the repair?  The joinery need was clear.... But what about paint?  Talking through the plans with Pete Ward,  it did seem pointless to be going to all the effort to achieve a breathable render while at the same time re-coating the window frames in an acrylic paint.   Pete's challenge to me was: why not use linseed paint?  Linseed, I learned, was the (breathable) naturally derived paint material which has been used in our buildings for centuries but which we have all but forgotten about in recent decades as acrylic paints became ubiquitous.   That made sense to me and so the windows spec was decided; 9 window popper out and off to joinery workshop for repairs to replace rotten edges and corners, all paint to be stripped off  and  repainted with linseed paint.  Easier said than done in the end ...







The windows were firmly on the critical path for the overall re-render because they needed to be repaired, repainted and back in place so that the third coat of lime could be rendered up to the window frame.   We had allocated 5 weeks for the windows to be repaired, stripped and repainted.  In the end we went wildly over the budgeted time on this - almost entirely due to difficulties stripping and painting.  Firstly, getting layers of modern paint and primer off hard wood proved extremely difficult.  We had to settle for 80-90% off  even with the most industrial-scale stripping agent.

Then came the experience of waiting for linseed paint to dry in the Irish climate.  The base coat is 50% oil and on its own took a month to dry.  Linseed paint is sensitive to UV light in terms of drying - the more the better.  The conditions we were working in were not ideal and everyone involved was, to their credit, making best efforts with a material new to them. All in all, it took more than 3 months for joinery, stripping and paint drying end-to-end.   In desperation, we had to get the frames back in place to allow the third coat of render to proceed while the windows themselves were still being painted and later assemble the windows on-site.  The paint wasn't truly try even then.  In fact, it was still a little sticky in October 4 months after they were re-installed!        



The scaffolding did afford a nice view!





So, looking back, we completely failed to manage the critical path properly. Scaffolding stayed up nearly two months longer than planned and the render finished much later than planned all due to delays with getting the windows back in and painted.  We were only saved from a mess by a combination of the patience and schedule flexibility of the Kevin, Pat and their painter Paul, the patient 'until finished' understanding of the scaffold hire company, and the fact that I opted (for unrelated reasons) late in the process to have a sacrificial coat of lime wash put on to the render (meaning the render work itself had an increased spec) smoothing the fact everyone was onsite longer than envisaged.

My takeaway lessons from the experience:

  • Linseed paint is a beautiful material and I will use it again in future (in fact I just have - in restoring the wrought iron entrance gate)
  • There is no need for tropical hardwood window frames if using breathable paint - knowledge I will apply any new windows I have made in future .... perhaps for the out-houses
  • Linseed paint is best applied in extremely thin coats (the more the better) and allowed to dry in the elements (wind and UV light).  I gather I can be used to paint in weather down to -2 centigrade
  • Allow time for it to dry even when applied thinly and with ideal drying conditions
  • Fully to complete the breathable windows+render comb, use a linseed and burnt sand mastic to seal the gap between the windows and the render    

The scaffolding finally came down in July 2014 by which time I needed a break from the renovation process!  The target of addressing the outside of the house had been achieved and it was time to breath out and see how it performs over winter 2014/15.  Finger crossed for a dry house!

I must say we were all very happy with how well the lime render looked when completed ...





Sunday, 26 October 2014

Commissioning and starting the Big Job

Completely removing of the external concrete render and putting back in place a lime render (such was would always have been on the house) was to be the fundamental step in making the house work properly once again.  Also the most expensive step.  Crucial, therefore to get it right.
 
For me, this meant two big decisions to make:
1) decide the detailed specification for the re-render
2) choose the best people available for the job

By now (early 2014) I was feeling on a bit of a roll.  The having hacked off all the lower external render (as high up as was possible without scaffolding), the stonework underneath could be clearly seen  which helped with estimating the raking, pointing and rendering job required.  With advice from Pete over the telephone, I was able to hone the specifications and give sensible consideration to questions that arose as I spoke about the job with potential contractors.

But I was still (scarily, as I look back) reliant on the contractors on the ground asking me the right questions to ensure nothing important got missed.  Good example was the windows.  Although only 12 years old some, if not all, had rotting frames because the cement around them was trapping moisture.  This was despite their being made of teak fully treated with primer etc.  Should these come out for repair while the cement around them was hacked off and the re-render underway? Very good question. The answer, after much thought and discussion, was 'yes, but'.  The windows saga will fill a future post.        

The other big specification question was the external finish.   The default full lime render involves applying 4 coats of lime resulting in a thick protective render which acts like a breathable 'blanket' which will absorb moisture (as did the cement render, through micro cracks) but - unlike cement - will allow that moisture evaporate away again through the action of wind and sun so it is not trapped in the stone wall underneath.  There are choices on colour of lime in the finish as well as whether the finish be hand or machine cast.

But you can also treat stone walls with lime short of a full 4 coat render.  And this ended up being the spec. question I spent most time exploring.  The hacking off revealed what to me seemed very attractive relieving arches over the windows at the front of the house.  They looked to me attractively vernacular country Georgian and I felt sad to glimpse them briefly only to lose sight of them again under 4 coats of render.      


Furthermore, the stone wall still carried colour from what seemed to be an old yellow lime wash.  If so, could I not instead have the walls re-pointed and lime washed so that the stonework could still be seen?  Was there not evidence from the yellow colour on the wall that this was how it had been at some stage in the past?

Aesthetically, pointing and limewashing appealed to me as an alternative to a render.  Pointed stone buildings can be seen in towns and villages up and down Ireland and looked so attractive.  However, at the back of my mind was unease that this might fail adequately to weather-proof the house.  Also, the following passage which I had read in Patrick McAfee's book Stone Buildings was ringing in my head:
'In Ireland practically every traditional stone building - farmhouse, townhouse or shop - was rendered ......The current fashion of removing renders is to be condemned as it is changing the original visual and aesthetic character of Irish towns, villages and individual houses.  It also creates problems with rain penetration, heat loss, deterioration of timber lintels, internal plasterwork and paint.'  
   
As well as Pete and the building contractors, I consulted the county council conservation officer and emailed Patrick McAfee, who kindly replied.  I was on a quest for some false reassurance which they are all too wise and professional to furnish.  To point and lime wash a house on an exposed site on the Atlantic coast of Ireland was taking a significant risk with rain penetration.  To do so would not break the primary conservation principle of being reversible.  By this I mean that if it proved the wrong choice, there would be nothing to undo - you would just have to apply the lime render on top the following year.  On the other hand, it risked doubling the eventual cost if it did prove the wrong choice.

Ultimately, the work was being done to retrieve a dry house.  Bearing this priority in mind, the spec. settled on full 4 coat render.  The one exception I negotiated with the contractors was the very sheltered east facing wall of the 19th century kitchen extension (interestingly, this later extension had the best quality stone in the house) where it was agreed to point the stone and apply a sacrificial lime wash.   

As for decision no. 2, I was determined, having seen the result when letting a modern bungalow builder lose on an old building,  only to use someone had good credentials in using lime and in working with old buildings.   Within that cohort, there was obviously a preference for a local person - in my case this mean County Clare - other things equal.  To begin, how best to search and select was a worry.  In the end though, based off my experience, I don't believe this need be problematic for anyone in Ireland. 

Nowadays, good practitioners seem to be around if you look carefully.  The county council website has a register of conservation professionals and the council conservation officer was generous with his time and willing to supplement what was on the website.  The Irish Georgian Society website http://www.igs.ie/ is an excellent resource which includes a skills register of specialist contractors as is the website of the Irish chapter of the Building Limes Forum http://www.buildinglimesforumireland.com.  I had detailed conversations and quotes from two contractors based in Clare specialising in working with lime - mostly on old buildings - and was happy that both met my criteria.  One of these was actually a referral - via a friend - provided by Irish Seed Savers Association!

The choice in the end was dictated partly by availability to start.  I went with Kevin, Pat and the team at http://www.midwestlime.com/  and have had no cause to regret that decision.  To round off a very wordy post, a few more pics once Kevin and the gang got going to finish hacking off the dreadful cement..